Comparison Of Ground Motion Prediction Equation Between China Wenchuan Area And The Central And Eastern United States

The May12,2008Wenchuan earthquake （Mw=7.9） was the largest eventoccurred in China in recent years. It was the most devastating, the most widelyspread and the most difficult relief earthquake disaster in the past60years inChina. And it resulted in a great tragedy for Chinese. Wenchuan earthquake wasrecorded by many strong motion stations, which were installed and operated byChina Earthquake Administration. Many of these stations had detailed sitegeological conditions. Thus, Wenchuan earthquake provides and rich strongmotion dataset for study on ground motion attenuation and site effect.Ground-motion attenuation relationship or so-called ground motionprediction equation （GMPE） is the critical basis of the compilation of seismicparameter zoning map and the seismic safety assessment in the engineering site.And GMPE has been always paid attention to earthquake engineering. ThePacific Earthquake Engineering Research Center PEER has carried out acomprehensive study on ground motion attenuation—a project called the NextGeneration of Ground-Motion Attenuation Models （NGA）. The NGA projectwhich was original for the western United States （NGA-West） not only led to anew round of hot trend in GMPEs, but also has been expended to the central andeastern United States （NGA-East）. However, GMPE study in the central andeastern United States is hindered by the lack of ground-motion observations,particularly from large earthquake （M6or larger）.Wenchuan earthquake occurred along the Long Men Shan Faults which islocated on the western border of Sichuan basin. Studies show that Sichuan basinand the Central and Eastern United States have similar geologic characteristics–stable continent region （SCR）. Thus, the GMPE could be similar in Sichuanbasin and the Central and Eastern United States. The purpose of this study is tocompare the GMPEs in Sichuan basin and the Central and Eastern United Statesby utilizing the strong motion recordings from Wenchuan earthquake. Thisincludes:1. Completely collect the strong ground-motion recordings, including theWenchuan mainshock data well recorded by the stations within rupture distancesof500km; the observation data recorded in52events Wenchuan aftershockswhich moment magnitudes are ranging from5.0to6.5; and recordings datarecorded in the two earthquakes in CEUS recent years. To process the databaseand to get peak ground acceleration （PGA）, peak ground velocity （PGV） and theseveral different period of response spectrum acceleration （PSA）. Then todevelop a new GMPE using in Sichuan Basin, China.2. Collecting and sorting the engineering geological condition data of217stations, to calculate and classify the site types of stations and to contrastanalogy analysis of geological condition between Sichuan SCR and CEUS SCRon the base of the average shear-wave velocities for the top20m （V（20）） and30m (V₃₀) computed and transformed by Chinese station geological data. Accordingto the similarities on geological structure and site condition of these two regions,to get a conclusion that Wenchuan earthquake data can be used in the research ofGMPEs in CEUS.3. To validate the GMPEs in CEUS using the small-medium aftershocksrecordings, founding that the GMPEs in CEUS conformed the attenuation trendof actual records. A conclusion could be got form using Wenchuan earthquakedate to develop the GMPs in CEUS and guessing the GMPEs in CEUS can beused in ground-motion estimation for large earthquake not only the small-medium earthquake. The comparisons show similarities between the GMPEs inWenchuan area and in CEUS.The results show that the GMPEs for Sichuan basin are similar to those forCEUS, and the strong motion records from the Wenchuan earthquake can beused for constraining GMPE as well as engineering analysis in CEUS.